Introduction to Organic Molecules & Functional Groups CHAPTER 11 Introduction to Organic Molecules & Functional Groups General, Organic, & Biological Chemistry Janice Gorzynski Smith

CHAPTER 11: Intro to Organic Molecules & Functional Groups Learning Objectives: Difference between organic and inorganic molecules Name characteristic features of organic compounds Draw organic compounds, including skeletal structures Identify common bond types, angles, and molecule shapes Name functional groups Understand polarity and its effect on solubility and boiling point Explain the difference between fat and water soluble vitamins Smith. General Organic & Biolocial Chemistry 2nd Ed.

CHAPTER 11: Intro to Organic Molecules & Functional Groups Lecture Outline: Define Organic Chemistry Review the shape of organic molecules How to Draw organic compounds Overview of functional groups Review intermolecular forces Review polarity Smith. General Organic & Biolocial Chemistry 2nd Ed.

Smith. General Organic & Biolocial Chemistry 2nd Ed. Organic Chem Definition Organic Chemistry is the study of compounds containing carbon. Both naturally occurring and synthetic compounds C, H, O, N, S, P, Halides (Cl, F, Br, I) Smith. General Organic & Biolocial Chemistry 2nd Ed.

Brainstorm examples of organic and inorganic compounds. Group Problem Brainstorm examples of organic and inorganic compounds.

Smith. General Organic & Biolocial Chemistry 2nd Ed. Organic Chem Definition Methane gas Pregnenolone; hormone in adrenal glad and brain FOXP2 protein Smith. General Organic & Biolocial Chemistry 2nd Ed.

Smith. General Organic & Biolocial Chemistry 2nd Ed. Organic Chem Bonding Covalent Bond? Valence electron? Octet Rule? Smith. General Organic & Biolocial Chemistry 2nd Ed.

Smith. General Organic & Biolocial Chemistry 2nd Ed. Organic Chem Bonding A COVALENT BOND shares a pair of electrons between atoms. non-metal to non-metal bond The OCTET RULE states that atoms of main group elements make bonds by gaining, losing, or sharing electrons to achieve an outer shell containing 8 electrons. How many valence electrons do Carbon and Hydrogen have? Oxygen? Nitrogen? Sulfur? Phosphorous? Chlorine? Smith. General Organic & Biolocial Chemistry 2nd Ed.

How many bonds does each atom need to satisfy the octet rule? C H O N Group Problem How many bonds does each atom need to satisfy the octet rule? C H O N S P

Draw these molecules: Ethane: C2H6 Cyclohexane: C6H12 Propene: C3H6 Group Problem Draw these molecules: Ethane: C2H6 Cyclohexane: C6H12 Propene: C3H6 Propyne: C3H4

Smith. General Organic & Biolocial Chemistry 2nd Ed. Molecule Shape Bond Angle VSEPR Theory: The most stable arrangement of atoms in a molecule maximized the distance between atoms and lone pairs. Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

What are the bond angles within the molecules? Group Problem Draw the lewis dot structures for water and ethanol. How many lone pairs of electrons do they have? What are the bond angles within the molecules?

What are the bond angles within the molecule? Group Problem Draw the lewis dot structure for ammonia. How many lone pairs of electrons does it have? What are the bond angles within the molecule?

Smith. General Organic & Biolocial Chemistry 2nd Ed. Molecule Shape Drawing Molecules SIMPLIFY! H H H H H C C C C H H H H H Use modeling kit! CH3CH2CH2CH3 Smith. General Organic & Biolocial Chemistry 2nd Ed.

Group Problem Practice: 1) convert to condensed structure 2) simplify further if possible 3) skeletal structure

Smith. General Organic & Biolocial Chemistry 2nd Ed. Functional Groups Overview Alkane Alkene Alkyne Aromatic C − C C = C Hydrocarbon Functional Groups Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Smith. General Organic & Biolocial Chemistry 2nd Ed. Functional Groups Overview Alkyl halides Alcohols Ethers Amines Single Bond to a Heteroatom Functional Groups Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Smith. General Organic & Biolocial Chemistry 2nd Ed. Functional Groups Overview Aldehydes Carboxylic Acids Esters Ketones Amides Carbonyl Functional Groups Use modeling kit! pentanal Ethanoic acid (or acetic acid) Methyl propanoate propanol Smith. General Organic & Biolocial Chemistry 2nd Ed.

Identify all of the functional groups Problem Identify all of the functional groups pentabromodiphenyl ether

Identify all of the functional groups Problem Identify all of the functional groups Estradiol Genistein A soy isoflavone

Group Problem Identify all of the functional groups (other then alkanes) in Gliadin C29H41N7O9

Properties of Organics Overview Organic compounds experience weaker intermolecular interactions because they form covalent bonds. no ion-ion interactions Usually clear or yellowish color Often a liquid or a gas at room temperature Lower melting points and boiling points relative to ionic compounds Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Properties of Organics Polarity The difference in electronegativity between two atoms bonded together creates a polar dipole moment. The more electronegative atom has a slight negative charge (more electron density). Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Group Problem What is the dipole moment of each bond, and what is the overall dipole moment for each molecule? Water Acetone Isopropanol Acetic Acid Diethyl Ether

Intermolecular Forces Properties of Organics Intermolecular Forces Intermolecular Forces weaker then intramolecular forces (bonding) London Dispersion Dipole-Dipole Hydrogen Bonding Instantaneous dipole-induced attractions that occur between all molecules, even non-polar. Partial charges of polar compounds attract each other . Strong dipole-dipole attraction when H is covalently bonded to a highly electronegative atom. No ion-ion interactions because all covalent bonds so no formal charges. Smith. General Organic & Biolocial Chemistry 2nd Ed.

Intermolecular Forces Properties of Organics Intermolecular Forces Intermolecular Forces weaker then intramolecular forces (bonding) London Dispersion Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Intermolecular Forces Properties of Organics Intermolecular Forces Intermolecular Forces weaker then intramolecular forces (bonding) Dipole-Dipole Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Intermolecular Forces Properties of Organics Intermolecular Forces Intermolecular Forces weaker then intramolecular forces (bonding) Hydrogen Bonding Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Rank the three intermolecular forces discussed in order of strength. Group Problem Rank the three intermolecular forces discussed in order of strength.

LIKE DISSOLVES LIKE Properties of Organics Solubility polar molecules dissolve in polar solvents nonpolar molecules dissolve in nonpolar solvents Polar Solvents Nonpolar Solvents Water: H2O Pentane: C5H12 Methanol: CH3OH Hexane: C6H14 Ethanol: CH3CH2OH Cyclohexane: C6H12 Acetone: (CH3)2CO Benzene: C6H6 Acetic Acid: CH3CO2H Toluene: CH3C6H5 Ammonia: NH3 Chloroform: CHCl3 Acetonitrile: CH3CN Diethylether: (CH3CH2)2O Use modeling kit! Smith. General Organic & Biolocial Chemistry 2nd Ed.

Group Problem Draw all of the solvents from the previous slide and prove they are polar or nonpolar.

Properties of Organics Water & Fat Soluble Vitamins Which type of solvent would the following molecules dissolve in? Use modeling kit! Vitamin A Vitamin B12 32 Smith. General Organic & Biolocial Chemistry 2nd Ed.

NH3   H  N   H   H    H  N  H    H   H N H H Molecules BONDING: Lewis Bond Theory strategy to tackle problems NH3 Start with the least electronegative element as the central element Surround the central element with the bonding elements and indicate their initial electrons Add extra electrons, from surrounding atoms, to the central atom to satisfy the octet rule Use multiple bonds if necessary   H  N   H   H    H  N  H    H   H N H H

 H   NH3  N H     H      H  N H N H H     H H Molecules BONDING: Lewis Bond Theory strategy to tackle problems  H   NH3  N H   Initial electron bookkeeping: Find the difference, this is the number of electrons that must be shared ÷ 2 to know the # of bonds shared Arrange atoms around the most electronegative element Final electron bookkeeping:   H Need: 3x(1H x 2 e-) + (1N x 8 e-) = 14 e- Have: 3x(1H x 1 e-) + (1N x 5 e-) = 8 e- (14 e-) – (8 e-) = 6 e- (6 e-) ÷ 2 = 3 bonds      H  N H N H H     H H